RNA recognition by arginine-rich peptide motifs

A ubiquitious class of RNA-binding proteins is distinguished by an arginine -rich motif: Such proteins function in transcription translation, RNA traff icking, and packaging. Peptide models are derived from viral regulatory pro teins, including the I virulence factors Tar and Rev of mammalian immunodef iciency viruses. Structures of model peptide-RNA complexes exhibit diverse strategies of recognition based in each case on structural transitions: Ind uced RNA structures contain noncanonical elements such as purine-purine mis matches, base triples, and flipped bases. Such elements enlarge and extend the RNA major groove to create specific peptide-binding pockets and surface s. The repertoire of bound peptide structures-beta-hairpin, alpha-helix, an d helix-bend-helix-reflects the diversity of induced RNA architectures. Thi s repertoire, reminiscent of primordial exon-encoded peptides, may recapitu late early events in the transition between RNA and protein worlds. Peptide -directed changes in modern RNA structures can provide a mechanism of signa ling in higher-order RNA-protein assemblies. (C) 1999 John Wiley & Sons, In c.